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SciNaPPS - Science, Neurology, and Psychiatry/Psychology Seminars - presents this free seminar on dopamine reward prediction in an ADHD model at the Brain and Mind Research Institute.

Presented by Dr Jeff Wickens, Principal Investigator at the Neurobiology Research Unit, Okinawa Institute of Science and Technology, in Japan.

Methylphenidate (Ritalin) is the most widely used and effective treatment for attention-deficit hyperactivity disorder (ADHD). Methylphenidate has a known cocaine-like pharmacological action on the dopamine transporter, but its therapeutic mechanism in ADHD is not completely understood.

Many pieces of evidence indicate that there is altered processing of reward in ADHD, with increased sensitivity to delay of reward and a greater than normal preference for immediate over delayed rewards.

Since dopamine is a key neurotransmitter in reward processing, modulation of reward processes by an action on dopamine is a possible mechanism for the effects of methylphenidate.

Here we show that dopamine release in response to a classically conditioned cue that precedes reward is deficient in an ADHD model, and that methylphenidate specifically rescues this anticipatory dopamine release, at doses commonly used in treatment of ADHD.

This specific action of methylphenidate provides a novel basis for its therapeutic action, in which facilitated release of dopamine by cues that predict reward is expected to bridge delays between actions and rewarding outcomes.

We propose that by increasing the anticipatory release of dopamine, methylphenidate enhances the ability to stay on task when reward is delayed.